Pi 2 Pi ack???

This question is answered

Hi Clients partner is using PI too. So I have a process flow like this. I send an IDOC to my PI system. My PI connects to the partner's Pi using HTTP/ XI protocol and my partners PI systems picks up this XI protocol message and post an IDOC in their SAP system. It is a reverse order for inboung IDOCs.

For the inbound IDOC scenario - I have to send ALEAUD ACk back. After going through SDN I was able to configure but the ack reaches only my PI system. How to I send this ack to the partners PI system such that the partner PI can propogate i to its ECC system.

What additional configuration is required to make sure that the ALEAUD acknowledgment sent back from the partner reaches our PI box and finally our SAP system? My partner Pi system can get the idoc ack but how does he pass it on to my PI box?